"Jeff Layton" <jlayton@xxxxxxxxxx> writes: > On Fri, 2019-09-06 at 17:26 +0100, Luis Henriques wrote: >> "Jeff Layton" <jlayton@xxxxxxxxxx> writes: >> >> > On Fri, 2019-09-06 at 14:57 +0100, Luis Henriques wrote: >> > > OSDs are able to perform object copies across different pools. Thus, >> > > there's no need to prevent copy_file_range from doing remote copies if the >> > > source and destination superblocks are different. Only return -EXDEV if >> > > they have different fsid (the cluster ID). >> > > >> > > Signed-off-by: Luis Henriques <lhenriques@xxxxxxxx> >> > > --- >> > > fs/ceph/file.c | 23 +++++++++++++++++++---- >> > > 1 file changed, 19 insertions(+), 4 deletions(-) >> > > >> > > Hi! >> > > >> > > I've finally managed to run some tests using multiple filesystems, both >> > > within a single cluster and also using two different clusters. The >> > > behaviour of copy_file_range (with this patch, of course) was what I >> > > expected: >> > > >> > > - Object copies work fine across different filesystems within the same >> > > cluster (even with pools in different PGs); >> > > - -EXDEV is returned if the fsid is different >> > > >> > > (OT: I wonder why the cluster ID is named 'fsid'; historical reasons? >> > > Because this is actually what's in ceph.conf fsid in "[global]" >> > > section. Anyway...) >> > > >> > > So, what's missing right now is (I always mention this when I have the >> > > opportunity!) to merge https://github.com/ceph/ceph/pull/25374 :-) >> > > And add the corresponding support for the new flag to the kernel >> > > client, of course. >> > > >> > > Cheers, >> > > -- >> > > Luis >> > > >> > > diff --git a/fs/ceph/file.c b/fs/ceph/file.c >> > > index 685a03cc4b77..88d116893c2b 100644 >> > > --- a/fs/ceph/file.c >> > > +++ b/fs/ceph/file.c >> > > @@ -1904,6 +1904,7 @@ static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off, >> > > struct ceph_inode_info *src_ci = ceph_inode(src_inode); >> > > struct ceph_inode_info *dst_ci = ceph_inode(dst_inode); >> > > struct ceph_cap_flush *prealloc_cf; >> > > + struct ceph_fs_client *src_fsc = ceph_inode_to_client(src_inode); >> > > struct ceph_object_locator src_oloc, dst_oloc; >> > > struct ceph_object_id src_oid, dst_oid; >> > > loff_t endoff = 0, size; >> > > @@ -1915,8 +1916,22 @@ static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off, >> > > >> > > if (src_inode == dst_inode) >> > > return -EINVAL; >> > > - if (src_inode->i_sb != dst_inode->i_sb) >> > > - return -EXDEV; >> > > + if (src_inode->i_sb != dst_inode->i_sb) { >> > > + struct ceph_fs_client *dst_fsc = ceph_inode_to_client(dst_inode); >> > > + >> > > + if (!src_fsc->client->have_fsid || !dst_fsc->client->have_fsid) { >> > > + dout("No fsid in a fs client\n"); >> > > + return -EXDEV; >> > > + } >> > >> > In what situation is there no fsid? Old cluster version? >> > >> > If there is no fsid, can we take that to indicate that there is only a >> > single filesystem possible in the cluster and that we should attempt the >> > copy anyway? >> >> TBH I'm not sure if 'have_fsid' can ever be 'false' in this call. It is >> set to 'true' when handling the monmap, and it's never changed back to >> 'false'. Since I don't think copy_file_range will be invoked *before* >> we get the monmap, it should be safe to drop this check. Maybe it could >> be replaced it by a WARN_ON()? >> > > Yeah. I think the have_fsid flag just allows us to avoid the pr_err msg > in ceph_check_fsid when the client is initially created. Maybe there is > some better way to achieve that? I guess the struct ceph_fsid embedded in the client(s) could be changed into a pointer initialized to NULL (and later dynamically allocated). Then, the have_fsid check could be replaced by a NULL check. Not sure if it would bring any real benefit, though. Want me to give that a try? Or maybe I misunderstood you question. > In any case, I'd just drop that condition here. Ok, I'll send v2 in a second, without this check. [ BTW, looks like my initial post didn't made it into vger.kernel.org. It was probably dropped because I screwed-up the 'To:' field in my email (no idea how I did that, TBH). ] Cheers, -- Luis
